The present invention relates to a system designed suitably for the digital dubbing of a reproduced signal which constitutes a part of a system designed for the conversion of a video signal into a digital signal and the recording of the digital signal on a plural number of channels by magnetic or optical recording.
As an example of a system for converting the video signal into a digital signal and recording the digital signal on a recording medium by magnetic or optical apparatus is a digital video tape recorder. It is extremely difficult for the code obtained from the video signal to be recorded, for example, by a single magnetic head, since such a code constitutes high-speed data of 100 Mb/second or higher. In order to cope with this problem, a technique which enables the code to be distributed for a plural number of channels and recorded simultaneously using a plural number of magnetic heads is used.
As for a method of distribution of the video code, there are the following three methods as have been proposed by Hirano et al. in the paper entitled "A Study on Variable Speed Rproduction of the Digital VTR" in SMPTE Journal, Vol. 92, No. 6 (June, 1983) pp. 636-641. The following are three methods for the distribution of a video code into three channels A, B and C.
(i) The high bits of each picture element are assigned to channel A, the medium bits to channel B and the low bits to channel C. PA1 (ii) Each picture element is assigned to the channels A, B, C, A, B, C . . . . PA1 (iii) The picture elements in left area of the picture are assigned to channel A, the picture elements in the central area to channel B and the picture elements in right area to channel C.
In each case of the aforementioned video code distribution methods, however, it is intended that the distribution-by-channel of what is called the composite signal consisting of a luminance signal and the chrominance signal, which have undergone processing for frequency division multiplexing, to be just like a NTSC signal.
On the other hand, for recording of a high-quality picture, it is considered preferable for the luminance signal and the chrominance signal to be recorded separately instead of being processed for frequency division multiplexing. As for what is called the component signal such as that discussed above, there is no previous publicly known example for optimization of the distribution by channel. Consequently, there is no previous publicly known method as to the digital dubbing of the reproduced signal relating to the method of video code distribution.